Spinning projectile for smooth bore guns



April 1966 M. F. ABELA 3,247,795

SPINNING PROJECTILE FOR SMOOTH BORE GUNS Filed April 1. 1964 39 44 58 5? Fig.9

INVENTOR.

MICHAEL F. ABELA ATTOENEYfi United, States Patent Claims. (Cl. 10238) This invention relates generally to ammunition for smooth bore firearms and especially to a shotgun shell incorporating a projectile of the nature of a slug that is capable, notwithstanding the absence of rifling in a gun barrel, of developing a spin while it is traveling through the gun barrel.

To improve the range, accuracy of travel and other ballistic characteristics of shotgun ammunition, particularly shells incorporating projectiles rather than shot, has long been a desideratum. Typically, shotguns have a rather short range relative to the range of a rifle; consequently, the use of slug-firing shotguns and shells is not infrequently permitted in circumstances in which the use of bullet-firing rifles and cartridges is prohibited. However, in hunting, especially animals larger than squirrels, rabbits and the like, the usefulness of slug-firing shells is hampered not only by the lack of range of the projectile but by its lack of ballistic accuracy. To provide a shotgun shell and projectile that can be used to better advantage is a major object of the present invention.

Other objects, advantages and features of the invention will be apparent from the description which follows and from the accompanying drawings, in which:

FIGURE 1 is a central longitudinal section through the chambered portion of a shotgun barrel showing the shotgun shell and projectile of the present invention, the projectile being shown in elevation;

' FIGURE 2 is acentral longitudinal section through the same shotgun barrel showing the projectile and wad as they appear after leaving the chambered portion of the barrel;

FIGURE 3 is a transverse section taken substantially in the plane represented by line 3-3 of FIGURE 2 with part of the leading end of the projectile shown in elevation;

FIGURE 4 is a transverse section through the shotgun shell showing the sleeve and wad as seen from the plane represented by the line 44 of FIGURE 1;

pearing in elevation in FIGURE '1;

FIGURES 6 and 7 show a modified form of projectile, the former comprising a transverse section in the plane represented by line 66 of FIGURE 7 and the latter a side elevation with part broken away substantially to the plane represented by line 77 of FIGURE 6; and

FIGURES 8 and 9 show another modification, the former comprising an elevation of the leading end of a differently formed projectilewith part broken away and the latter a central longitudinal section taken sub stantially in the plane represented by line 9-9 of FIG- URE 8.

FIGURES 1, 2 and 5 to 9 are on a like but somewhat enlarged scale; FIGURES 3 and 4, on a much larger scale.

In FIGURES l, 2 and 3, the shotgun barrel is designated 1; the chamber, at the rear of the barrel in FIG- URE 1, is designated 2. Shown in firing position in the chamber 2 is a shotgun shell 3 made up of an elongated paper sleeve 4 turned over on itself at 4a, an encompassing metal cap 5 at the opposite end thereof, a typical primer assembly 6 held in place in conventional fashion in the cap 5, and a propellant charge 7 of a composition of one of the kinds commonly used in shotgun shells.

Forwardly of the propellant charge 7 is a wad 8 made of a synthetic resin such as nylon, the same taking the form a shallow cylinder provided with a central void 9.

The trailing end of such void is spanned by a thin frangible closure 10 which may be an integral portion of the wad. The plane of the closure extends normally to the longitudinal axis of the shell. The void itself is shaped after the fashion of a truncated quadrilateral pyramid; accordingly, the frangible closure portion 10, which is coextensive with the truncated end of the void, is square in shape: see FIGURE 4. Forwardly of the wad 8 is projectile 11, which is held in place by the turned-over portion 4a of sleeve 4. i

The projectile 11, seen to best advantage in FIGURES 1, 2 and 5, comprises an elongated generally cylindrical body portion 12 of a dense metal such as lead or a suitable lead alloy which, at its trailing end, is undercut or beveled inwardly at 13. Adjacent, but spaced toward the rear from its leading end, it is provided with an annular channel 14. The beveled portion .13 and the channel 14 cooperate to hold in place an outer body portion in the form of a nylon jacket 15 provided, at its trailing and leading ends, with inwardly directed circular flanges 16 and 17, respectively. The flange 16 is so shaped as to enable it to coact with and complement the bevel 13. The flange 17, which is shaped after the fashion of an annulus, is so proportioned as to permit it to enter into the annular channel 14. The jacket 15 is located on and affixed to the body portion 12 of the projectile 11 by forcing and telescoping it forwardly from the trailing end thereof until the flange 17 lodges in the channel 14 with a snap fit at which time the flange 16 contacts and interlocks with the bevel 13.

The periphery of the jacket '15 is formed as shown in FIGURES l and 5 with annular serrations consisting of a multiplicity of axially spaced circular ridges 18 which individually are of triangular cross section: see FIGURE 2. Of substantially the same external diameter as the internal diameter of the paper sleeve 4, such ridges are at least as large in diameter as the interior diameter of the main portion of the barrel 1 forward of the chamber 2. This is advantageous both in relation to the conditions obtaining in the shell 3, wherein the entry of contaminants from the forward end of the shell is prevented, and in relation to the conditions obtaining in the portion of the barrel 1 forward of the chamber 2, wherein the ridges 18, by reason of their circular contacts against the inside surface of the barrel, prevent or at least minimize blow-by of the high pressure gaseous decomposition products derived from explosion of the propellant charge 7.

The nylon wad 8, which intervenes between the propellant charge 7 and the projectile 11, is of substantially the same diameter as the internal diameter of the sleeve 4 and tends to serve the same purposes as the ridges 18 in preventing blow-by.

Within the body portion 12 and largely to the rear of the central zone thereof is an axial open-ended cylindrical chamber 19 of the same diameter as the internal diameter of the flange 16 on the jacket 15. The cylindrical chamber 19 is in axial alignment with the pyramidal void 9 in the wad 8. Its open end adjoins the wide end of the void. Forward and extending as continuation of it is a relatively short frusto-conical chamber 20 the narrow end of which is in substantially the same transverse plane as the leading end of the jacket 15. Forward of and of the same diameter as the truncated end of the frusto conical chamber 20 is a shallow cylindrical chamber 21 encompassed by a short cylindrical head portion 22 formed integrally with the body portion 12 of the projectile 11. The head portion 22 is of smaller diameter Patented Apr. 26, 1966 Y than the diameter of the outer body portion of the projectile so that during travel of the latter through the barrel of the firearm a clearance is maintained between the periphery of the head portion and the internal surface of the barrel. As shown, however, the diameter of the head portion 22 perferably is less than that of the metal body portion 12.

In the shell 3, the turned over end portion 4a of the sleeve 4 appearing in FIGURE 1 closes off the forward end of an annular space 23 surrounding the cylindrical head portion 22 of the projectile 11, engaging such head portion in sealing relation. When the projectile 11 moves forward to enter that portion of the barrel 1 forward of the chamber 2, the turned-over portion 4a of the shell 4 is pushed out of the way or unfolded. As a result, the closed-off annular space 23 becomes an open-ended annular space 24 that at its forward end is in open communication with the interior of the barrel 1: see FIG- URE 2. Because the turned-over portion 4a of the paper shell 4 no longer overlaps the cylindrical portion 22, the open-ended space 24- is longer from end to end than the closed-off space 23-.

The projectile 11 is provided within the cylindrical head portion 22 thereof with a series of four transversely directed bores 25, 26, 27 and 28 arranged each with a tangential component or along a chord of a circle as shown in FIGURE 3 in such manner that each extends at a right angle to the nearest two of the other three bores. None of the four bores projects very far beyond its intersection with the chamber 21. At their outer ends, seen, for example, in FIGURE 5, the four bores terminate in gas expulsion orifices 25a, 26a, 27a and 28a: see FIG- URE 3.

Although all four bores appear to be tangent to the periphery of the cylindrical chamber 21, the proximate side of each is continuous with the interior chamber of the projectile, openings designated 25/), 26b, 27b and 28b being formed where the bores 25, 26, 27 and 28 respectively intersect the cylindrical chamber 21. Thus there is open communication between the void 9, the cylindrical chamber 19, the frusto-conical chamber 20 and the cylindrical chamber 21, each in turn, and, through the openings 25!), 26b, 27b and 28b, with the tangential bores 25, 26, 27 and 28. The gaseous decomposition products originating in and upon explosion of the propellant charge 7 are directed into the transversely directed bores 25, 26, 27 and 28. From the latter they escape into the openended space 24 separating the cylindrical head portion 22 and the barrel 1.

Forward of the cylindrical portion 22 the projectile 11 has a frusto-conical head 29 that is dished, as at 30, to

permit of the packaging of shells in end-to-end relation without premature functioning of their primer assemblies.

Referring to FIGURE 1, when the firing pin (not shown) strikes the primer assembly 6, detonation of the primer composition results, followed immediately by detonation of the propellant charge 7. The gaseous decomposition products of the explosion break through the frangible portion of the wad 8 virtually at once. FIGURE 4 shows the forward face of the wad Iii-before the primer composition is detonated; i.e., while the propellant charge 7 is still intact. Lines 19a, which coincide with the narrow end of the pyramidal void 9, define the lateral limits of the frangible portion 10.

In the interests of easy frangibility, the portion 10 is scored in an X-shaped pattern along diametrically extending intersecting lines ltlb, not sufiiciently heavily to pierce or sever the plastic material or make for separation prior to firing but heavily enough to weaken it materially. The gaseous decomposition products emanating from the propellant charge 7 rupture the fragible portion 10 on the lines 10b, producing triangular flaps the hinges of which coincide with the lines Ida. These flaps bend forwardly within the pyramidal void 9 as illustrated diagrammatically in IGURE. 2..

In FIGURE 2, the projectile 11 has not separated from the wad 8, which acts as a follower as the projectile travels lengthwise of the barrel 1 under the influence of pressure exerted against the wad by the gaseous products of decomposition of the propellant charge 7.

From what has been said above, it will be apparent that gaseous decomposition pro-ducts finding their way through the opening in the wad formed by the rupture of the frangible portion 10 proceed sequentially through the chambers 19, 20 and 21 in the projectile 11. Following the paths indicated by the arrows in FIGURE 3, they make their escape in the form of high energy jets to the interior of the barrel 1 through the gas expulsion orifices 25a, 26a, 27a and 28a. The reaction of the gases on the projectile 11, because of the offset or non-radial arrangement of the jets issuing from the orifices and the cumulative effect of the several jets, is such as to apply a torque and impart a spin or rotation to the projectile 11 about its longitudinal axis that continues even after the projectile leaves the barrel muzzle. The spin thus imparted continues throughout the flight of the projectile and results in a longer and ballistically more desirable type of trajectory without excessive yawing or tumbling. Thus the projectile 11, by virtue of its internal construction, achieves the desirable ballistic characteristics possessed by a bullet discharged from a firearm the barrel of which is provided with helically extending lands and grooves.

A variant of what is shown in FIGURES 1 to 5 appears in FIGURES 6 and 7. Except at its leading end, projectile 31 is similar throughout to the projectile 11. Instead of having four bores in its leading-end arranged tangentially to and spaced equi-angularly about a shallow central cylindrical chamber, the projectile 31 has a chamber 32 of relatively small diameter and two radially aligned coaxial bores 33. The latter provide com-munication between the chamber 32 and two laterally spaced parallel bores 34 that extend normally to the bores 33. Whereas the outer ends of the bores 33 are plugged as at 35, the outer ends 34a of the bores 34 are open and function as gas expulsion orifices. The result is the production of a spinning action comparable to that characterizing the projectile 11.

Another variant appears in FIGURES 8 and 9, in which projectile 36 is characterized, among other things, by a solid body portion 37 of lead or a lead alloy in the periphery of which are formed ridges 38 corresponding generally to the ridges 18 in the jacket 15 characterizing each of the two previously described embodiments of the invention. At the leading end of the projectile 36 are a cylindrical portion 39, a frusto-conical head 40 and a dished area 41. These parts are similar, respectively, to the cylindrical portion.22, the frusto-conical head 29 and the dished area 30 of the projectiles 11 and 31.

At the trailing end of the projectile 36 is a centrally disposed, relatively wide cylindrical chamber 42 and, forward of and adjoining it as an extension, a shallow frustoconical chamber 43. Communicating with the latter are four spaced longitudinally extending parallel bores 44. These bores are themselves in communication with as many laterally extending bores 45. Where the latter interrupt periphery 39a of cylindrical portion 39, the openings form gas expulsion orifices each with a tangential component. The action of the projectile is similar to that of the projectiles 11 and 31 notwithstanding the absence of a separate jacket on body portion 37. The omission of the latter is representative of what can be done, by way of modification, by persons skilled in the art without departing from the spirit of the invention.

It is intended that the patent shall cover, by summarization in appended claims, all features of patentable novelty residing in the invention.

What is claimed is:

1. In a shotgun shell, the combination comprising a propellant; a wad forwardly of the propellant characterized by a frangible central portion; and a projectile forwardly of the Wad with its trailing end in engagement therewith but out of contact with the frangible portion thereof, said projectile having between its trailing end and its leading end a multiplicity of generally annular serrations the outermost portions of which are of a diameter sufiicient to permit them to engage the interior'surface of a shotgun barrel.

2. In a shotgun shell, the combination comprising a propellant; a wad with a pyramidal central opening forwardly of the propellant; and, forwardly of the Wad, a projectile characterized by a leading end and a trailing end, a multiplicity of generally annular serrations therebetween, a central opening aligned with the pyramidal opening in the wad, and a plurality of laterally directed gas expulsion passages connecting said central opening with the exterior surface of the leading end of the projectile.

3. A combination according to claim 2 wherein at least two of said gas expulsion passages parallel the longitudinal axis of the projectile.

4. A combination according to claim 2 wherein at least twoof said gas expulsion passages extend normally to the longitudinal axis of the projectile.

5. A shotgun shell projectile taking the form of a generally cylindrical slug comprised of a main portion of dense metal and, interlocked with said main portion to resist axial separation, a synthetic resin jacket of generally cylindrical shape at least a portion of the outer surface References Cited by the Examiner UNITED STATES PATENTS 2,090,533 8/1937 Howdeshell 102-50 2,322,751' 6/1943 Studler 102-92.5 2,345,619 4/ 1944 Moore 102-92.5 2,476,291 7/ 1949 Garber 102-95 2,820,412 1/ 1958 Beeuwkes 102-91 X 3,011,404 12/1961 Russell et al 102-95 X 3,058,420 10/1962 Tanner et a1. 102-98 3,062,145 1 1/19621 Morgan et a] 102-38 3,063,376 11/ 1962 Powell 102-51 3,065,696 '11 1962 Kleinguenther 102-51 FOREIGN PATENTS 226,47 2 4/ 1943 Switzerland.

BENJAMIN A. BORCHELT, Primary Examiner.

R. F. STAHL, Assistant Examiner. 

1. IN A SHOTGUN SHELL, THE COMBINATION COMPRISING A PROPELLANT; A WAD FORWARDLY OF THE PROPELLANT CHARACTERIZED BY A FRANGIBLE CENTRAL PORTION; AND A PROJECTILE FORWARDLY OF THE WAD WITH ITS TRAILING END IN ENGAGEMENT THEREWITH BUT OUT OF CONTACT WITH THE FRANGIBLE PORTION THEREOF, SAID PROJECTILE HAVING BETWEEN ITS TRAILING END AND ITS LEADING END A MULTIPLICITY OF GENERALLY ANNULAR SERRATIONS THE OUTERMOST PORTIONS OF WHICH ARE OF A DIAMETER SUFFICIENT TO PERMIT THEM TO ENGAGE THE INTERIOR SURFACE OF A SHOTGUN BARREL. 